Question

Daca x,y E R si x+y=12,iar x*x-y*y=48,determinati x si y.
Dau funda!

Answer 1

[tex]x+y=12\\ x*x-y*y=48\\ x^2-y^2=48\\ (x-y)(x+y)=48\\ 12(x-y)=48=\ \textgreater \ x-y=4\\ Si\ de\ aici\ avem\ sistemul:\\ \left \{ {{x+y=12} \atop {x-y=4}} \right. \\ Le\ scadem:2y=8=\ \textgreater \ y=4\\ x+4=12=\ \textgreater \ x=8[/tex]